In the extraction, processing and refining, storage and combustion of hydrocarbon and carbon based compositions (e.g. crude oil, synthetic crudes, natural gas, coal and coke) significant quantities of toxic substances are encountered and/or produced. These substances include, for example, hydrogen sulfide gas, mercaptans, SOX gases (e.g SO2 and SO3) and NOX gases (e.g NO, NO2 and N2O). Hydrogen sulfide and mercaptans are often extracted with crude oil. Carbon dioxide, carbon monoxide and SOX gases can be produced during crude oil processing and refining. NOX gases can be produced upon combustion of hydrocarbon based fuels. Furthermore, post combustion fumes from coal fired power stations, coking plants and steel production plants generally contain one or more of these gases. There is therefore a continuing need for the development of compositions and processes which permit the removal of these gases from hydrocarbon based streams, chimneys and exhausts.
H2S scavenging compounds typically comprise amine adducts and the preparatory methods thereof often require the use of complex reaction protocols and environmentally toxic reaction materials. For example, GB 2409859 describes an oil-soluble sulfur scavenger including substantially monomeric aldehyde-amine adducts from the reaction of at least one sterically hindered primary or secondary amine and a molar excess of at least one aldehyde, or a donor thereof.
US Patent Application No. 2005/0214199 describes a large surface area manganese oxide compound used for removing pollutants such as NOX, SOX, and CO by adsorption and oxidation. The manganese oxide is prepared by the reaction of a bivalent manganese salt with alkali metal permanganate and hydroxide solutions in the presence of ion-exchanged water under specific reaction conditions. Removal rates of up to 35% are reported with respect to carbon monoxide.
Thus, there is a need for further compositions for use in the removal of toxic substances. There is also a need for compositions which can be prepared by way of relatively straight forward and economical reaction protocols. There is also a need for the preparation and isolation of compositions which have multifunctional use in a number of applications, such as those described above.